[RFC PATCH v1] libcamera: controls: Generate macro for each control

[Barnabás Pőcze]

Hi


2025. 03. 17. 19:54 keltezéssel, Jacopo Mondi írta:
> Hi Barnabás
> 
> On Mon, Mar 17, 2025 at 07:11:46PM +0100, Barnabás Pőcze wrote:
>> Generate a macro in the form of LIBCAMERA_HAS_$VENDOR_$MODE_$NAME
>> for each control so that its existence can be checked easily
>> and without extra version checks.
>>
>> Signed-off-by: Barnabás Pőcze <barnabas.pocze at ideasonboard.com>
> 
> Do we really want this ?

Good question, hence the RFC; I don't think there is a very nice
way to discover (and use) controls at comptime/runtime. Also note
that the control namespaces already have their own existence macros
(e.g. `LIBCAMERA_HAS_RPI_VENDOR_CONTROLS`).

> Applications should discover controls
> programmatically.

What do you have in mind? Looking up the numeric id in the appropriate
`ControlIdMap` by the (namespace, name) pair?


Regards,
Barnabás Pőcze


> 
> Or is this useful for ABI compliance validation ?
> 
>> ---
>>   include/libcamera/control_ids.h.in | 1 +
>>   1 file changed, 1 insertion(+)
>>
>> diff --git a/include/libcamera/control_ids.h.in b/include/libcamera/control_ids.h.in
>> index 5d0594c68..8f037589d 100644
>> --- a/include/libcamera/control_ids.h.in
>> +++ b/include/libcamera/control_ids.h.in
>> @@ -49,6 +49,7 @@ extern const std::array<const ControlValue, {{ctrl.enum_values_count}}> {{ctrl.n
>>   extern const std::map<std::string, {{ctrl.type}}> {{ctrl.name}}NameValueMap;
>>   {% endif -%}
>>   extern const Control<{{ctrl.type}}> {{ctrl.name}};
>> +#define LIBCAMERA_HAS_{{vendor|upper}}_{{mode|upper}}_{{ctrl.name|snake_case|upper}}
>>   {% endfor -%}
>>
>>   {% if vendor != 'libcamera' %}
>> --
>> 2.49.0
>>